If you’d like to really clean your Tupperware, here’s a great trick...

Tupperware and other plastic containers stain easily – especially if you put tomato sauce in there. 

Soaking them in detergent might help but that often leaves them with a soapy smell and flavor. Coffee grounds to the rescue. Just add a drop of detergent and a heaping spoonful of used coffee grounds to the container and scrub it around until the stains disappear, then rinse with warm water. The grounds help absorb and remove the greasy residue and smell much better than soap alone.